In architecture, structural engineering, and construction, building or bridge components are typically fabricated according to a specific set of design specifications. Such components are often expensive because they are customized to fit the exact specifications of a particular building or bridge project.
During fabrication and construction, errors in the building or bridge specifications, manufacturing tolerances in the building or bridge components, or other unforeseen circumstances may cause a change in a structure's geometry, typically requiring new parts to be ordered. This may cause significant delays and add substantial costs to a building or bridge project.